Synthesis gas catalysts

Katzer, J. R., AES and Reaction Studies of Poisoning by Sulfur and Regeneration of Metal Synthesis Gas Catalysts. Annual Report submitted to the U.S. Department of Energy under Contract No. E(1 l-l)-2579, January, 1978. 

Catalyst deactivation is a common pathological phenomenon in many industrial reactions. In the case of hydrocarbon steam reforming to produce synthesis gas, catalyst activity loss may be due to coke arising from carbon deposition. Carbon lay-down usually occurs via undesired side reaction, namely ... 

For methanol from synthesis gas, catalyst compositions based on Cu-Zn-Al-Sc oxides and calcination temperature of the catalyst precursor were optimised for achieving maximum activity. A combination of GA and a radial basis function network turned out to be more robust than GA alone. 

Nobody was as surprised as Haber when he was informed about the discovery of mixed iron-based catalysts And so it is iron, with which Ostwald worked at first, and which was then tested hundreds of times in pure form, which now acts only in impure forms. I see again how one should follow every trace until the end. A most welcome property of these catalysts was their extraordinary stability. As long as no catalyst poison is present in the synthesis gas, no deactivation of catalysts has been observed in the lower layers of modern large-volume converters even after more than a decade of operation, and with extremely pure synthesis gas catalysts can even serve up to twenty years. ... 

An example of such recychng in a parallel reaction system is in the Oxo process for the production of C4 alcohols. Propylene and synthesis gas (a mixture of carbon monoxide and hydrogen) are first reacted to ra- and isobutyraldehydes using a cobalt-based catalyst. Two parallel reactions occur ... 

COPPERALLOYS-WROUGHT COPPERAND WROUGHT COPPERALLOYS] (Vol 7) -catalysts for synthesis gas [NITROGEN FIXATION] (Vol 17)... 

Fischer-Tropsch Process. The Hterature on the hydrogenation of carbon monoxide dates back to 1902 when the synthesis of methane from synthesis gas over a nickel catalyst was reported (17). In 1923, F. Fischer and H. Tropsch reported the formation of a mixture of organic compounds they called synthol by reaction of synthesis gas over alkalized iron turnings at 10—15 MPa (99—150 atm) and 400—450°C (18). This mixture contained mostly oxygenated compounds, but also contained a small amount of alkanes and alkenes. Further study of the reaction at 0.7 MPa (6.9 atm) revealed that low pressure favored olefinic and paraffinic hydrocarbons and minimized oxygenates, but at this pressure the reaction rate was very low. Because of their pioneering work on catalytic hydrocarbon synthesis, this class of reactions became known as the Fischer-Tropsch (FT) synthesis. 

Dimethyl Ether. Synthesis gas conversion to methanol is limited by equiUbrium. One way to increase conversion of synthesis gas is to remove product methanol from the equiUbrium as it is formed. Air Products and others have developed a process that accomplishes this objective by dehydration of methanol to dimethyl ether [115-10-6]. Testing by Air Products at the pilot faciUty in LaPorte has demonstrated a 40% improvement in conversion. The reaction is similar to the Hquid-phase methanol process except that a soHd acid dehydration catalyst is added to the copper-based methanol catalyst slurried in an inert hydrocarbon Hquid (26). 

Natural Gas Upgrading via Fischer-Tropsch. In the United States, as in other countries, scarcities from World War II revived interest in the synthesis of fuel substances. A study of the economics of Fischer synthesis led to the conclusion that the large-scale production of gasoline from natural gas offered hope for commercial utiHty. In the Hydrocol process (Hydrocarbon Research, Inc.) natural gas was treated with high purity oxygen to produce the synthesis gas which was converted in fluidized beds of kon catalysts (42). 

A similar process to SMDS using an improved catalyst is under development by Norway s state oil company, den norske state oHjeselskap AS (Statod) (46). High synthesis gas conversion per pass and high selectivity to wax are claimed. The process has been studied in bubble columns and a demonstration plant is planned. 

There are some chemicals that can be made economically from coal or coal-derived substances. Methanol and CO are used to make acetic anhydride and acetic acid. Methanol itself can be made from synthesis gas over a copper-2inc catalyst (see Feedstocks, coal chemicals). 

Methane. The largest use of methane is for synthesis gas, a mixture of hydrogen and carbon monoxide. Synthesis gas, in turn, is the primary feed for the production of ammonia (qv) and methanol (qv). Synthesis gas is produced by steam reforming of methane over a nickel catalyst. 

Steam Reforming. In steam reforming, light hydrocarbon feeds ranging from natural gas to straight mn naphthas are converted to synthesis gas (H2, CO, CO2) by reaction with steam (qv) over a catalyst in a primary reformer furnace. This process is usually operated at 800—870°C and 2.17—2.86... 

A fundamentally different reaction system is under development by Air Products and Chem Systems (23). In this system, synthesis gas is bubbled through a slurry consisting of micrometer-sized methanol catalyst particles suspended in a paraffinic mineral oil. The Hquid phase serves as the heat sink to remove the heat of reaction. 

Other Specialty Chemicals. In fuel-ceU technology, nickel oxide cathodes have been demonstrated for the conversion of synthesis gas and the generation of electricity (199) (see Fuel cells). Nickel salts have been proposed as additions to water-flood tertiary cmde-oil recovery systems (see Petroleum, ENHANCED oil recovery). The salt forms nickel sulfide, which is an oxidation catalyst for H2S, and provides corrosion protection for downweU equipment. Sulfur-containing nickel complexes have been used to limit the oxidative deterioration of solvent-refined mineral oils (200). 

The saturated, cleaned raw synthesis gas from a Texaco partial oxidation system is first shifted by use of a sulfur resistant catalyst. Steam required for shifting is already present ia the gas by way of the quench operation ia the generator. The shifted gas is then processed for hydrogen sulfide and carbon dioxide removal followed by Hquid nitrogen scmbbiag. 

---